Thermodynamics and isotope effects of the vanadium--hydrogen system using differential heat conduction calorimetry

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458940· OSTI ID:6334837

Luo, W; Clewley, J D; Flanagan, T B ^[1]

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1. Chemistry Department, University of Vermont, Burlington, Vermont 05405 (USA)

The V--H (D) systems have been investigated using reaction calorimetry at 298 and 323 K over hydrogen contents from H (D)/V=0{r arrow}{approx}1.8. Relative partial molar enthalpies have been determined by absorption of small increments of hydrogen in the single phase regions; for regions where two solid phases coexist, integral or plateau enthalpies are obtained by absorption (desorption) of either large or small amounts of hydrogen. The following calorimetric results were obtained for the two solid phase plateau regions: {vert bar}{Delta}{ital H}{vert bar}=40.6 kJ/mol H, 40.8 kJ/mol D for ({alpha} + {beta}) and {vert bar}{Delta}{ital H}{vert bar}=19.1 kJ/mol H and 23 kJ/mol D for ({beta}{prime}+{gamma}) and ({alpha}{prime}+{epsilon}), respectively. Calorimetric data, relative partial molar enthalpies are also given for the single phase regions. Several phase boundaries are intersected as the hydrogen contents increase in this temperature range and the behavior of the enthalpies at the phase boundaries has been determined and is discussed in relation to the nature of the coexisting phases.

• OSTI ID: 6334837
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 93:9; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
CALORIMETRY
DEUTERIUM
DIAGRAMS
ELEMENTS
ENTHALPY
HYDRIDES
HYDROGEN
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPE EFFECTS
ISOTOPES
LIGHT NUCLEI
MEDIUM TEMPERATURE
METALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PHASE DIAGRAMS
PHYSICAL PROPERTIES
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VANADIUM
VANADIUM COMPOUNDS
VANADIUM HYDRIDES